Open up DS3 tool
Go to Driver Manager, select the driver and click "load driver"

Go to the profiles tab
Now select "Playstation 3" mode and click the pink "Enable" button

Select "Playstation 3" (Even if you're using an Xbox controller), and click on "Options"

Make Button 5 Digital L2
and Button 6 Digital R2
Save changes

If your controller isn't working you may just need to wake it up by pressing the middle button. If nothing is showing up under "Connected game controllers" you might just need to restart your computer.